Dual Fuel Guage Rage
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Joined: Mar 2005
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Dual Fuel Guage Rage
I just bought a used '86 Ford F150 with an "in-line" 6-cylinder and dual tanks.
The fuel guage reads empty for both tanks, despite the fact that I just dumped $ 60.00 to fill them both up. (For 60 bucks i wanna see evidence of the gas's existance.)
I've troubleshooted the system to the point that I am sure that (at least one of the) problem(s) is in the (what's the word here...) "float" of the front tank. I know this because if I disconnect the electrical connector to the Front tank and short one side to the other, the gas guage reads full at the instrument panel.
I can't do the same thing to the rear tank because it is mounted too close to the underside of the bed for me to reach in. I would have to remove the tank to get access to the wiring.
The problem is that NEITHER tanks register fuel, and the circuit is common between the two tanks after the fuel tank selector switch. So the Rear Tank's problem is either the same as the front (bad or stuck "float" in the tank) or it is in the Rear Tank's wiring between it's float and the Fuel Tank Selector Switch.
First I am hoping to check my reasoning here. Does this sound right ?
Second, it seems unlikely to me that BOTH "floats" would go bad. I have some electronics troubleshooting experience and two simultaneous problems are very rare. But I cannot seem to think of a commmon cause for these problems. Can anyone help ?
For what it is worth, I believe I have "ruled out" the following as causes for this (these) problem(s):
Fuel Guage
Fuel Tank Selector Switch
Front Tank's Wiring Circuit
Which leaves the Front Tank Float, the Rear Tank Float and the Rear Tank's Wiring as causes. Is there a way that just one of these could cause BOTH symptoms ?
Thanks in advance.
The fuel guage reads empty for both tanks, despite the fact that I just dumped $ 60.00 to fill them both up. (For 60 bucks i wanna see evidence of the gas's existance.)
I've troubleshooted the system to the point that I am sure that (at least one of the) problem(s) is in the (what's the word here...) "float" of the front tank. I know this because if I disconnect the electrical connector to the Front tank and short one side to the other, the gas guage reads full at the instrument panel.
I can't do the same thing to the rear tank because it is mounted too close to the underside of the bed for me to reach in. I would have to remove the tank to get access to the wiring.
The problem is that NEITHER tanks register fuel, and the circuit is common between the two tanks after the fuel tank selector switch. So the Rear Tank's problem is either the same as the front (bad or stuck "float" in the tank) or it is in the Rear Tank's wiring between it's float and the Fuel Tank Selector Switch.
First I am hoping to check my reasoning here. Does this sound right ?
Second, it seems unlikely to me that BOTH "floats" would go bad. I have some electronics troubleshooting experience and two simultaneous problems are very rare. But I cannot seem to think of a commmon cause for these problems. Can anyone help ?
For what it is worth, I believe I have "ruled out" the following as causes for this (these) problem(s):
Fuel Guage
Fuel Tank Selector Switch
Front Tank's Wiring Circuit
Which leaves the Front Tank Float, the Rear Tank Float and the Rear Tank's Wiring as causes. Is there a way that just one of these could cause BOTH symptoms ?
Thanks in advance.
Moderator
Joined: Jan 2001
Posts: 56,984
Likes: 2,738
From: Virginia
You are on the right track, your troubleshooting is sound. The possiblity does exist that both sending units could be bad because:
1. The previous owner may have left it this way for a long time and never fixed it.
2. Ford sending units are notorious for going bad.
Once you pull the unit out of the tank, bend back the little tabs on the housing and take a look inside. You may find the wiper broke off, and I have soldered these back together with pretty good success. Also make sure the float actually "floats" and is not full of gas.
1. The previous owner may have left it this way for a long time and never fixed it.
2. Ford sending units are notorious for going bad.
Once you pull the unit out of the tank, bend back the little tabs on the housing and take a look inside. You may find the wiper broke off, and I have soldered these back together with pretty good success. Also make sure the float actually "floats" and is not full of gas.
Cargo Master
Joined: Aug 2003
Posts: 3,237
Likes: 3
From: Belleville, Ontario
Welcome to FTE !
Considering that you have 2 tanks, it might make life alot easier if you take the pick-up bed off the truck. At least unbolt the bed & prop it up so you can get at the rear tank without having to drop the straps etc.,etc.
AL.
AL.
